A receptacle-filling system in a balance as well as its constituent parts, in particular a weighing object carrier and a source container device are disclosed. The balance used with the system has a weighing compartment and a balance housing that contains a weighing cell and forms the rear wall and the floor of the weighing compartment.
There are a multitude of possibilities for using a balance in a laboratory. Laboratory balances are frequently used for filling substances into receptacles, for example in preparing measured doses of powdery or liquid substances and the like. As a rule, a person entrusted with this task will have developed a working technique that is to a large extent optimized for the prevailing circumstances, i.e., the accessory equipment of the balance, the particular placement of the balance at the work station, the arrangement of the supply containers at the work station, the size and number of the vessels to be filled, etc. Nevertheless, there is a frequent need for further development of these boundary conditions with respect to improved ergonomics. In regard to this opportunity for improvement, the accessory equipment of the balance takes a key position.
A balance which is described in U.S. Pat. No. 6,557,391 B2 has a weighing compartment, a balance housing containing the weighing cell and forming the rear wall and the floor of the weighing compartment, a carrier device which serves to receive the weighing object and is attached to a cantilevered extension of the weighing cell to which a receiving seat for calibration weights of a calibration device is attached. The cantilevered extension has a coupling arrangement which reaches through passage openings in the rear wall of the weighing compartment and serves as a means for removably attaching the weighing object carrier to the cantilevered extension. The floor of the weighing compartment extends as a closed separating wall between the receiving seat for the calibration weights and the weighing object carrier. The weighing object carrier can be configured as a level grate or in another embodiment as a holder for one or more laboratory vessels, where the holder can also be configured so that it can swivel about an axis. This opens up a multitude of application possibilities for the balance and thus ensures improved manual operating conditions from an ergonomics point of view.
A balance which is described in U.S. Pat. No. 6,603,081 B2 has a weighing compartment, a balance housing containing the weighing cell and forming the rear wall and the floor of the weighing compartment, a carrier device which serves to receive the weighing object and is attached to a cantilevered extension of the weighing cell. A fixed holder system is attached to the rear wall of the weighing compartment, which allows weighing compartment accessories to be fastened at different heights above the floor of the weighing compartment. A holder for laboratory devices or an intermediate floor can be attached to the holder system, where the intermediate floor can be useful as a place on which to set substance containers, tools, etc. The holder system is configured so that a laboratory device or the intermediate floor is easy to fasten or to remove. The laboratory devices envisaged here include for example dosage delivery devices for powdery or liquid substances.
The balances of the foregoing description are not optimized in every respect for the dispensing of substances, in particular if the substance quantities are small and therefore have to be dispensed into receptacles with a narrow opening. For example when using a generally known type of balance, the receptacle which is to be weighed while being filled cannot be set up at the location in the weighing compartment that is ergonomically most appropriate for the fill-weighing process. Furthermore, when a substance to be filled into a receptacle has to be transferred out of a source container that is located outside of the weighing compartment, a time-consuming manipulation is required as one frequently has to pass several times through an opened window of a draft shield which is normally present, and as a result the thermal equilibrium in the weighing compartment can be disturbed by air drafts.
In the case of the balance described above which belongs to the known state of the art, wherein the source container for the substance to be dispensed can be placed inside the weighing compartment for example on the intermediate floor, the space situation in the weighing compartment often requires carefully controlled hand movements so that a source container that may have been set on the intermediate floor does not get knocked over. There is further the risk that the air in the weighing compartment gets warmed up too much if the user's hand remains in the weighing compartment too long while performing the filling operation.